This invention relates to flexible fluoropolymer-containing composites, to a method of making the composites by film lamination techniques, and to protective garments and other articles made from such novel composites, as well as to a method for making such articles. Articles made with composites according to this invention are chemically resistant and the composites are sufficiently flexible to permit fabrication of protective garments. Fire resistant composites can also be made.
Protective garments are currently available which provide some measure of chemical protection. These garments can be made from non-woven spun-bonded polyethylene (Tyvek) or polyester (Sontara), and from laminates of Tyvek with polyethylene or Saran. Other materials, such as butyl or neoprene elastomers, fluoroelastomers and chlorinated polyethylene can also be used in protective garments. For example, U.S. Pats. Nos. 4,421,878 and 4,423,183 teach that cured fluoroelastomer films (Viton) may be useful as a coating in safety apparel. Each of these materials, however, is permeable to or degraded by some classes of chemicals. They are not resistant to the complete spectrum of toxic and hazardous materials potentially encountered in hostile environments. Moreover, garments of these materials require flame resistant oversuits where both chemical and fire protection are necessary. Elastomeric materials, such as Viton or butyl rubber, are irreversibly contaminated by some hazardous materials, such as nitrobenzene and cannot be cleaned Furthermore, the barrier properties of these materials are detrimentally affected by decontamination, and therefore articles made of these materials are not suitable for reuse.
U.S. Pat. No. 4,165,404 describes a process for producing coated laminates of knit or woven fabrics with a thick fluorinated copolymer sheet using an interlayer of low melt viscosity copolymer. The composites thus formed are not sufficiently flexible for use as garments, and are so structured as to be specifically suitable for molding rigid articles.
Fire resistant protective garments have been made from spun-laced Nomex. These materials have no chemical resistance, however, due to the open structure of the fabric. Previous efforts at coating Nomex spun-laced fabrics to achieve a material which is both chemical and fire resistant have resulted in loss of the flexibility necessary for clothing.
Accordingly, it is an object of the present invention to provide flexible composites which may be resistant to both fire and hazardous materials for use in protective garments and other articles such as covers and shelters. Fire resistant materials can be obtained using a fire resistant flexible substrate.
It is a further object of this invention to provide a method for seaming materials having a melt adhesive on both sides. This method uses heat sealed seams, or a combination of sewing and heat sealing. In the latter case, the sewn seam is never exposed to the challenge agent.